CODEWITHSUNDEEP
pythonpandasdataframe
user1083734
user1083734

Reputation: 5195

Extracting all rows from pandas Dataframe that have certain value in a specific column

I am relatively new to Python/Pandas and am struggling with extracting the correct data from a pd.Dataframe. What I actually have is a Dataframe with 3 columns:

data =

Position Letter Value
1        a      TRUE
2        f      FALSE
3        c      TRUE
4        d      TRUE
5        k      FALSE

What I want to do is put all of the TRUE rows into a new Dataframe so that the answer would be:

answer = 

Position Letter Value
1        a      TRUE
3        c      TRUE
4        d      TRUE

I know that you can access a particular column using

data['Value']

but how do I extract all of the TRUE rows?

Thanks for any help and advice,

Alex

Upvotes: 12

Views: 41806

Answers (2)

Olaleye Abiola
Olaleye Abiola

Reputation: 77

You can wrap your value/values in a list and do the following:

new_df = df.loc[df['yourColumnName'].isin(['your', 'list', 'items'])]

This will return a new dataframe consisting of rows where your list items match your column name in df.

Upvotes: 0

Andy Hayden
Andy Hayden

Reputation: 375845

You can test which Values are True:

In [11]: data['Value'] == True
Out[11]:
0     True
1    False
2     True
3     True
4    False
Name: Value, dtype: bool

and then use fancy indexing to pull out those rows:

In [12]: data[data['Value'] == True]
Out[12]:
   Position Letter Value
0         1      a  True
2         3      c  True
3         4      d  True

*Note: if the values are actually the strings 'TRUE' and 'FALSE' (they probably shouldn't be!) then use:

data['Value'] == 'TRUE'

Upvotes: 23

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